Users encounter blank or black screens when logging in to Windows Server 2012 R2 machines, and they are unable to connect to the server through an Remote Desktop Protocol (RDP) connection. On the server console, some system processes (such as Task Manager) might not run.

Solution 1

Caution! Refer to the Disclaimer at the end of this article before using Registry Editor. 

Change invalid mfapphook value in the following location:

Key Location: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows

Entry Name: AppInit_DLLs

Entry type: String

New Entry Value: mfaphook64.dll

c:\progra~2\citrix\system32\mfaphook64.dll

Solution 2

1. Change the Enhanced Desktop Experience policy to Prohibited for Server 2012 R2 Delivery Groups.

2. Access the policy by editing Citrix Policies in Active Directory Group Policy Management Editor or by using the Studio Policy node.

Use the Group Policy Management Editor

1. For Group Policy, create a new policy object that is linked to the Organization Unit or Domain where the Server 2012 R2 servers reside.

2. Edit the policy and go to the Computer Configuration > Policies > Citrix Policies folder.

3. Create a new policy named Disable Enhanced Desktop Experience for Server 2012R2, and click Next.

4. Locate Enhanced Desktop Experience and click Add.

5. By default, the policy is set to Allowed. Change it to Prohibited and click OK.

6. Under Filters, assign the policy to a specific Server 2012 R2 Delivery Group.

7. Click Next and verify Enable this policy is selected.

8. Click Create and exit from Group Policy Management Editor.

9. Perform a Group Policy Update or restart on all servers to ensure that the change take effect.

Use the Studio Policy Feature

1. In Studio, access the Policy Node and choose Create Policy.

2. In the search box, type Enhanced  Desktop Experience.

3. Click Select.

4. Change the setting to Prohibited and click OK.

5. Assign the policy to the appropriate Delivery Group or Organizational Unit and click Next.

6. Create a new policy named Disable Enhanced Desktop Experience for Server 2012R2, and click Next.

7. Ensure Enable Policy is selected and click Finish.

Log off user sessions for the change to take effect.